Underreamer



Mai'ch ZO, 192s. 1,663,048

E. S. HARTSON UNDERREAMER Filed April 11,1927

Patented Mar. 20, 192.) p

tree? i meant I ARLS. nartrson, or Los Antennas, murmurs. 4

"UNDEBREAMERKM Applicationfiled April 11,3827; Serial Nb'. 182,723?

application for'lU. S. Letters Patent filed by me February 26,1927,'Serial N 0. 171,212.

. Further 'objectsotmy invention are tov provide simple and efiicient'means foreffe'ot inga positive outward Or -expanding movement of the bits r cutter blades to'the underreamer and, likewise, for; positively retracting or drawing said bits or cutter blades into'the shell or housing, jWhicll bit actuating means is operated by a tubular mandrel having rightandileft hand threads andwith which cooperates a pair of nuts or bushings and a conical member, and, further, to provide automatically acting-means =for alter.- na-tely effecting engagement between thenuts orbushings and the conical member toelevate and lower :the sam'ewithin' the housing of the underreamer and consequently project and retract the bits that are associated with,

the conical member, and which automatic ac tuation of the parts is accomplished without the necessity of rotatingjthe threadedmandrel which forms :a partwof the drill-tube anti-clockwise; or: toward the left hand. I

With the foregoing and other objects in view, my invention consists in certain-novel features of constructionand arrangement of parts that will hereinafter be more' fully described andclai-med and illustrated in the accompanying drawing, in which-:

Fig.1 is averticahsection takenlength wise through the center of an underreamer constructed in. accordance with my invention and showing the-bits or cutter blades in their fully expanded posit-ions. Fig. 2 is an enlarged-horizontal section taken 0nwthe line 2-.2 of'Fig. 1.1 j Y Fig. 3 isa horizontalfsection takenv on the line: 3- -3 of. Fig.1. V

Fig. d is a detail section taken-on the line of Fig. 1. Fig.5 isa section taken onithe line-B es of Fig. 1 and looking upwardlyjagainst the.

underside of the conical member that actuatesthe bits. v

Referring by'numerals to the accompanying drawings, which illustrate a prac-tical embodiment of my invention, 10 designates a hollowcyllndrical shell thatt'orms a housing for the :parts of the underreamer and'eX tending axially therthrough, is a: tubular mandrel 11 that is provided with" externally arranged quick acting :right and left "hand threads12 and 13, respectively. The. ends of this thradedmandrel are arranged-for rotation in bushings *13' =.that1-are seated in'ftheiends 30f-shell-1O*'and thes upper end "of said mandrel. is -conne'cted to' the 'lower fendof the 'drill tube The'lower end at the. mandrel: below thefihousinga 10" is the body otadrill. h

Arranged fon vertical movement- Q within ber 14 providedwith anaxially arranged 75. the housing 10, is a tapered or conical mem--" bore -15q for the accommodation 015 the threaded mandrel "and mounted 1 to rotate freely in the upper end of the bore 15',='-is a nut or bushing 16'havi'ng; internally an ranged short left. hand threads 17 that engage they'letthand thread-13 on'mandrel :11. j H i Carriedby the nut or bushing 16," is a-jven tically. disposed. pin: 18 that fis norm-ally forced upward by a spring 19 and the lower end'of thispin that projects below-the nut o'r'bushinggis' adapted to engage against the shoulder- 20 tllQlZ lSQfOIli'lGdP at the "end of a concentric groove 21, 1 and rWhlCh latter is formedin theftop of the conical member 141. This groove 21 gradually toward the shoulder 20. I

Formed-through. the wall of mandrel-11 just below the upper one-of the bushingsal3', isran' aperture 22 within which is arranged a check valve 23" carryinga pin '24 that norincreases 'in depth mally projects beyond-the face of'the man'- drel-=1L and arranged on-this pin "behind theva lve 23,'is an expansive coil spring-25 that tends to move the valve-inwardly so "as to'close the-inner end otthe -apertu-re '22.

ice I During "drilling :operations, the pressure of the water vand mud that constantly ,flows through the drill tube T and man'drel,-l1 exerts pressure on check valve 23 20 hold the same off its seat at-the innerendpftheap eiture 22 and-thus the .Z tpi'ojects be yond the surface of the mandrel and forms a stop to limit the upward movement of the nut or bushing 16. Loosely mounted in the lower end of the axial bore 15, is anut or bushing 26 having 'internal threads 27 that engage iirtl e right hand thread 12 on mandreljll andcarried by thelower portion of'the nut or bushing, is a disk 28 through which passes a pair of pins 29. Arranged in the disk 28 beneath these pins, are coil springs 30 that normal ly exert upward pressure on sald pins and connected to the lower ends of said pins below the disk 28, is a larger disk 31 having a centrally arranged opening 32 for the accommodation of mandrel 11.

Formed on the interiorof the wall of shell 10,,are lugs 33 that are adapted to serve as stops to limit the upward movement of the disk 31 and said stops being located so that the disk engages against said stops just before the upper end of pin; 18 in nut or bushing 16 strikes againstthe upper end of the housingv 10. a

Formed in theunderside of conical member '.14,fare:concentric arcnate .grooves- 34, each of whlclr gradually. decreases m depth V member 14, are two or more-longitudinally disposed slots '36 that are substantially 'T- shaped in cross section and in which are arranged for sliding movement the T-shaped inner ends of bits or cutters 37. These bits or cutters areiarranged for sliding movement through slots or openings 38 that are formedin the wall'of housing 10.

In the operation of my improved underreamer and before'the sameis connected to the "drill tu'be'and lowered into the well,

the mandrel 11 is rotated so as to permit the conical member i14't'o move downward within the shell10' toits lower limit of movement and, as a result" of this downward movement of the conical member, the bits or cutters 37 'will' be retracted or drawn into the shell or housing, due to the engagement between the inner ends of said bits and "the T-shaped slots in said conical member.

,When' the bits are properly positioned within the housing, their outer edges lie flush with or slightly below the outer surface of the housing and thus, as the underreamer is lowered into the well casing, there will be nothing to interfere with its free downward movement. The underreamer is now connected to the well tubing T and, as the latter is lowered, the underreamer will move downward until-it is positioned just below the lower end of the casing.

The drill tube is now rotated in the usual mannerclockwise, or toward the right hand,v

upper portion and the engagement of the threads of nut or bushing 26 with the right hand thread 12 on mandrel 11 will'cause said nut or bushing to move upwardly until the upper ends of pins 29 pass into the concentric a-rcuate groove 34 and finally engage against the shoulders "35"a't the ends of said grooves and, following this engagement, which is in effect the locklng of the nut or bushlng .-t01 the conical.-mernber,. said nut or bushing will cease'to rotate, but, owing to the rota-'- tion of the mandrel, said nut and theconical member 14 to which it is locked, will be elevated on the mandrel" and as such'movement takes place, the bits 37 will be'eX- I panded or forced outward through: the openings 36 in housing 10. r

As the conical member 14 reaches its upper limit of movement within the housing,

the upper end of nut or bushing 16 will engage against projecting pin 24, which func- 'tions as a stop and which pin isheld in its projected position by the pressure of the mud and water circulating through the drill tube and mandrel and,-followingthis enf'gagement of the upper nutagainst' pin 24, all parts of the underreamer will rotate with the drilltube and mandrel as an integral structure and the projected or expanded bits 37 will cut and ream away the earth below the latter to be lowered after the V reaming operations. 1 V i At thecom'pletiOn' of the underream ng operations and' when it is desired to retract thecutters so as to lower the underreamer or elevate the same through the casing, the pressure onthe mudandwater that is "circulati'ng through/the drill tube is relieved,

position above nut ward a slight distance, or until the upper 'end of pin 18 strikes against the upper end 05 the lower end of thecasing so as to permit of the housing 1 0,;which action moves said pin downward against the-pressure of its spring and the lower endofsaid pin enters groove 21 and engages against the shoulder 20 at the'end thereof.

This action is in effe'cta and simultaneous with such action, disk 31 engages stop lugs 33 and, as the conical member continues to move a short'distance upward to its-limit of upward movement, the pins 29 will be withdrawn from the grooves 34, thereby unlocking-nut 26 from the lower end of conical member-14 and said: nut, by its own weight and'theiweight of the disk 31, will immediately move downward onmandrel 11 to the lower portion of the chamber within housing 10.

The drill tube T continues to rotate toward the right hand and the engagementiof locking of the nut -16 to the upper end of conical member 14 tea s the threads 17 on-nut' 16 wit-lithe left hand thread'lion the mandrel will causesaid nut to, move downwardly on; the mandrel,

thereby. forcing conical member 142 :--down :ward and consequently retracting or withthe housing by the alternate automatic ldck- I ing of nuts 'or bushings to the lends of said conical member, and which nuts or bushings have engagement with the right or left hand threads of a tubular mandrel, the latter forming a part of the drill tube.-

It will be understood that minor changes in the size, form and construction of the various partsrof my improved. unde'rreamer may be made and substituted for those here,

in shown and described withoutdeparting from the spirit of my invention, the scope of which is set fort-h in the appended claims. I claim as my invention:

1. In an underreamer, a housing, a tubular mandrel extending axially through said housing, said mandrel having right and left hand threads, a conical member arranged within the housing, cutter blades arranged for movement through the wall of the housing, the inner portions of which cutter blades have inter-engagement with said conical member, nuts loosely mounted in the ends of said conical member, one of which nuts engages in the right hand thread of the mandrel, the other nut having engagement with the left hand thread of the mandrel and automatically acting means for effecting an alternate locking of said nuts to the ends of said conical member. i

2. In an underreamer, a housing, a tubular mandrel extending axially through said housing, said mandrel having right and left hand threads, a conical member arranged within the housing, cutter blades arranged for movement through the wall of the housing, the inner portions of which cutter blades have inter-engagement with said conical member, nuts loosely mounted in the ends of said conical member, one of which nuts engages in the'right hand thread of the mandrel, the other nut having engagement with the left hand thread of the mandrel, automatically acting means for efiecta ing an alternate locking of said nuts to the ends of said conical member and a'pressure actuated check valve arranged'in the upper portion of the mandrel and functioning as a stop to *limit 'the upward movement of the nutrat'the upper end ofsaid conical member.

3. 'In'a'n' underreamer, a-housing, aconioal member within; said'housing, cutter blades 1 arranged formovement;throughfop'nings-in the wall of said housing, the "inner portion of which cutterblades-haveinter-engagemcnt with said :-'conica-lmember, a j tubular mandrel extending axially through; said housing and conical member, i said mandrel having right and left hand threads and meansarranged at the endsoffsald conical member andyhaving' engagement respec -tively-witl1 the right andlefthand threads V of the mandrel for alternately locking said conical member tosaid mandrel toefi'ect vertical movement of said in said housing;

4.- 11112111 .unde'rreamer," a housing; a conicala' member within" said housing; cutter blades arranged for movement through openings in the wall of said housing, the in ner portion of which cutter blades have in-- ter-engagement with said conical member, a tubular mandrel extending axially through dr'el having right and left hand threads, means arranged .atthe endstof said conical member and having engagement respectively with the right and left hand threads of the mandrel for alternately locking said conical member to said mandrel to effect vertical conical member withv said housing and conical member, said manmovement of said conical member within said housingand a pressure actuated check valve in the upper portion of the mandrel,

which check valve functions as a stop to limit the upward movement of the conical member within said housing.

, 5. In an underreamer,'a housing, a conical member within said housing, cutter blades arranged for movement through openings in the wall of the housing, the inner ends of which cutter blades have sliding engagementwith said conical member, a tubular mandrel extending axially through said housing and conicalmember, nuts loosely mounted in the ends of the conical member and having threaded engagement respectively with the right and left hand threads of the mandrel, the ends of the conical member being provided with shoulders and spring-held pins carried by said nuts and adapted to engage the shoulders in the ends of said conical member to lock said nuts to said conical member.

1 6. In an underreamer, a housing, a conical member arranged. therein, cutters ar-,

ranged'for operation though the wall of said housing, the inner ends of which cutters having sliding engagement with said conical member, a tubular mandrel extending ax- 'ially through said housing and conical member, which mandrel is arranged for rotation inthe ends of the housing, said mandrel having right and left hand threads, nuts ice I loosely arranged in the ends of saidconical member and having engagement respectiyely with the right and left hand threads of ethe mandrel, means for automatically 'locking the lower one offsaid nuts to the lowerend of said conical memberwhen the latter is in the lower portionofthehousing and means for automatically "locking. the upper one. of

said nuts "to the upper end of saidconical member when the latter isin the upper por tion of said housing. i

7 In an underreamer, a housing, a conical .member arranged therein, cutters a1"- ranged for-operation though the all ofsaid 1 housing; the inner ends of which cutters having slidingengagement with said conical 7 member, a tubular mandrel extending axially through said housing and conical member,

which mandrel is arranged for rotation in' the ends of the housing, said mandrel hav ing right andle'ft handthreads, nuts loosely I arranged in the ends of saidconical member and having engagement respectively, With jthe vright and left hand threads of the mandrel, means for automatically locking the lower one" of said nuts to. the; lower 'endof said conical member when the latter is in means between the upper one of said nuts and theupper end of said conical member is engaged.

: EARL fs. HARTSON.

In testimony whereof I affix my signature.- 

